Accessory power tap / fuse

[cheapjeep2]

I am installing some electronics that I want to turn off / on with the ignition / accessories.  I need a place tap power from.  Can anyone recommend a fuse location or a place where I can tap into a 12 v power source that is not continually on?

[WNY]

should be some spare taps in the fuse box under the hood or in the foot well that turn off with the ignition.

[plus 3 golfer]

These fuses are hot with the Ignition Relay energized: F14, F16, F19, F23, F26, F85, F86.

 

[jackalopetx]

I have a related question-- I need a power source for a dash camera but I want constant power even with ignition turned off. Can I tap the fuse box for that? 

[plus 3 golfer]

I have a related question-- I need a power source for a dash camera but I want constant power even with ignition turned off. Can I tap the fuse box for that? 

In the footwell under the glove box is the BCM fuses.  F58 and F63 should be spare slots (may have a fuse in it but not used) where one side is hot at all times (test with volt meter).  Then, find a fuse tap to plug in the spare slot.  

 

I assume you want "hot all the time" to run the cam in park mode.  One word of caution: the C-Max 12 volt battery has a reserve capacity of only 60 minutes which converts to about 25 Ah.   Most car batteries are around 100+ minutes which equates to about a 42+ Ah.  So, the cam draw in park mode and the potential recording draw when parked could be enough to drain the C-Max battery if you don't start the car for several days.

 

For example, if your park mode draw averages around 500 mA, you should be able to go around 70+ hours based on typical battery discharge curves before the battery discharges to about a 50% level.  So, try to find a camera with very low power requirements in park mode.  We are still not sure how low the C-Max battery can discharge before the car won't start (operate the modules and relays to connect the HVB to the DC/DC converter).  If it is down to say 10 % state of charge, you could probably go a week. 

Edited August 3, 2017 by Plus 3 Golfer

[jackalopetx]

In the footwell under the glove box is the BCM fuses.  F58 and F63 should be spare slots (may have a fuse in it but not used) where one side is hot at all times (test with volt meter).  Then, find a fuse tap to plug in the spare slot.  

 

I assume you want "hot all the time" to run the cam in park mode.  One word of caution: the C-Max 12 volt battery has a reserve capacity of only 60 minutes which converts to about 25 Ah.   Most car batteries are around 100+ minutes which equates to about a 42+ Ah.  So, the cam draw in park mode and the potential recording draw when parked could be enough to drain the C-Max battery if you don't start the car for several days.

 

For example, if your park mode draw averages around 500 mA, you should be able to go around 70+ hours based on typical battery discharge curves before the battery discharges to about a 50% level.  So, try to find a camera with very low power requirements in park mode.  We are still not sure how low the C-Max battery can discharge before the car won't start (operate the modules and relays to connect the HVB to the DC/DC converter).  If it is down to say 10 % state of charge, you could probably go a week. 

 

Thanks. Is there a specific type of fuse tap to use or are they all the same? Do you get + and - off the same fuse, or do you just get power and ground to another one?

[obob]

These fuses are hot with the Ignition Relay energized: F14, F16, F19, F23, F26, F85, F86.

 

Hot with Ingnition Relay On.PNG

 

Thanks.  What a time saver.  I emailed the info to myself to double down on not losing it.  

[plus 3 golfer]

Thanks. Is there a specific type of fuse tap to use or are they all the same? Do you get + and - off the same fuse, or do you just get power and ground to another one?

A fuse tap simply plugs into the existing fuse slot.  The fuse that was in the fuse slot plugs into the fuse tap.  There is also a wire off the load side of the fuse tap.  Thus, you have a positve wire lead to connect to the camera.  

 

You will also need to find a good ground point.  There should be a ground point around the lower right hand A-pillar. You may have to remove a panel to get to it.  Look for a larger black-white wire maybe bolted to a stud in the area.  Also, you should be able to use any part of the frame as a good ground you can find near the BCM fuses.

[WanderingSingers]

Pretty sure we are following the hints you've written.  Have added a fuse tap with a 25A fuse on on one of the spares below the passenger dash to plug in the the Brake Buddy system with a 12v adapter.  Connected to a ground.  Have 12+ volts before plugging anything in,.  BrakeBuddy hums.  Other checking, we are getting 4.3v (including with a 12v extension cord).  No clue.  The fuse tap is from PICO, we've found out now that it is made for 10amp but is all we find at NAPA.  At Amazon we find some taps to 20/25amp.  Any clues why we aren't getting a full 12v out of this and what we need to do differently?

 

Thanks for any and all suggestions.  

Maxie

[Treywija]

I dont know of a specific spot in the engine bay, but finding an accessory circuit on the fuse panel thats in the glove box is super easy. As long as you dont need more than 10 or 15a, you can use a fuse tap to do it. Takes a few seconds.